摘要：
Background: Qingzhuan tea (QZT) is classified as compressed dark tea and has been an essential daily commodity for ethnic minority communities in China 's border areas. It boasts unique flavor characteristics and health benefits, captivating the attention of consumers both domestically and internationally. However, the QZT industry 's historical closed nature and lengthy processing cycle have impeded a comprehensive scientific understanding and evaluation of this tea, as well as hindered the overall healthy development of the industry. Scope and approach: This article provides a comprehensive overview of the research progress on QZT, covering defluoridation techniques, processing technology, flavor characteristics, chemical composition, microbial communities, health benefits, and their underlying mechanisms. Key findings and conclusions: A technology system aimed at reducing fluoride levels in tea, known as "appropriate fertilization -selection of low -fluorine tea tree varieties -control of raw material tenderness and growing period, " has been proposed. Through the implementation of specific processing techniques, QZT exhibiting an orange -red infusion color, a mellow taste, and an aged aroma. During the key pile fermentation process, microorganisms release extracellular enzymes that initiate enzymatic and moist heat reactions, resulting in oxidation, hydrolysis, polymerization, and secondary metabolic conversions. These reactions serve as the underlying foundation for the distinctive sensory attributes of QZT. The regulation of microorganisms plays a vital role in attaining the desired flavor of QZT. Moreover, QZT encompasses a diverse array of bioactive constituents, which offer numerous health advantages such as antioxidative properties, anti -obesity and anti -diabetes effects, modulation of the intestinal microbiota, and alleviation of non-alcoholic fatty liver.
摘要：
Drying is the final and essential step in tea processing. It contributes a lot to the formation of tea flavor quality by a series of complicated and violent thermochemical reactions, such as degradation reaction, Maillard reaction, redox reaction, isomerization reaction, etc. However, the mechanism of specific thermochemical reaction is unclear. Here, by comprehensively summarizing the thermochemical reactions of the main chemicals, including polyphenols, lipids, amino acids and carbohydrates, etc., during tea drying with particularly focus on their contributions of thermal drying on the flavor including color, aroma, and taste, we found that thermal degradation is the dominant thermochemical reaction, directly affecting the taste and color of tea, and thermal oxidation of lipids and Maillard reaction mainly contribute to form tea aroma. More interesting was that high temperature enhanced nucleophilicity of phenolics, allowing them to easily trap carbonyl substances to form small molecular adducts (i.e. EPSFs) or polymers, which could interfere other thermochemical reactions, and then alter the flavor quality of tea. Over all, this review provides updated scientific evidence for in-depth exploration of thermochemical reactions towards tea precision processing.
通讯作者：
Jian'an Huang<&wdkj&>Zhonghua Liu<&wdkj&>Jian'an Huang Jian'an Huang Jian'an Huang<&wdkj&>Zhonghua Liu Zhonghua Liu Zhonghua Liu
作者机构：
[Hongzhe Zeng; Kuofei Wang; Changwei Liu; Jie Ouyang; Shuai Wen; Fang Zhou; Jingyi Tang; Wenwen Fang; Lin Yue; Jian'an Huang; Zhonghua Liu; Hongzhe Zeng Hongzhe Zeng Hongzhe Zeng; Kuofei Wang Kuofei Wang Kuofei Wang; Changwei Liu Changwei Liu Changwei Liu; Jie Ouyang Jie Ouyang Jie Ouyang; Shuai Wen Shuai Wen Shuai Wen; Fang Zhou Fang Zhou Fang Zhou; Jingyi Tang Jingyi Tang Jingyi Tang; Wenwen Fang Wenwen Fang Wenwen Fang; Lin Yue Lin Yue Lin Yue; Jian'an Huang Jian'an Huang Jian'an Huang; Zhonghua Liu Zhonghua Liu Zhonghua Liu] Key Laboratory of Tea Science of Ministry of Education, National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha, China
通讯机构：
[Jian'an Huang; Zhonghua Liu; Jian'an Huang Jian'an Huang Jian'an Huang; Zhonghua Liu Zhonghua Liu Zhonghua Liu] K;Key Laboratory of Tea Science of Ministry of Education, National Research Center of Engineering and Technology for Utilization of Botanical Functional Ingredients, Co-Innovation Center of Education Ministry for Utilization of Botanical Functional Ingredients, Key Laboratory for Evaluation and Utilization of Gene Resources of Horticultural Crops, Ministry of Agriculture and Rural Affairs of China, Hunan Agricultural University, Changsha, China
摘要：
(1) This study may be the first study to evaluate the effects of oolong tea with different storage time in db/db T2DM mice.(2) All three aged oolong tea extracts (2001, 2011, 2020) can effectively alleviate type 2 diabetes mellitus (T2DM), and 2011 aged oolong tea extract exhibited relatively optimal ability to alleviate T2DM.(3) With storage time of oolong tea increasing, oolong tea’s ability to inhibit fat ectopic deposition in liver increases and the ability to activate INSR/IRS/PI3K/AKT/GSK‐3β/GYS‐mediated hepatic glycogen synthesis signaling pathway decreases. Abstract An important concern for tea consumers is whether appropriate storage can effectively improve the ability of oolong tea to alleviate type 2 diabetes mellitus (T2DM). In this study, the antidiabetic effects of three aged oolong tea (2001, 2011, and 2020) extracts (aged TEs) in db/db T2DM mice were investigated and compared for the first time. The results showed that aged oolong tea extracts (aged TEs) alleviated the abnormal fasting blood glucose levels, lipid profiles, insulin resistance, and reduced ectopic fat deposition in liver. Moreover, aged TEs alleviated T2DM‐related tissue damage and activated insulin receptor (INSR)/insulin receptor substrate (IRS)/phosphatidylinositol‐3 kinase (PI3K)/phosphatidylinositol‐3 kinase (AKT)/glycogen synthase kinase 3 beta (GSK‐3β)/glycogen synthase (GYS)‐mediated hepatic glycogen synthesis signaling pathway. In addition, aged TEs altered gut microbiota composition and gut metabolite profiles associated with T2DM. Together, all three aged TEs (400 mg/kg/day in mice, a human equivalent dose of 7 g/60 kg/day), especially 2011, can effectively alleviate T2DM, and proper storage can effectively improve the ability of oolong tea to alleviate T2DM.
摘要：
Liquid chromatography-mass spectrometry (LC-MS) combined with multivariate analysis were used to characterize the nonvolatile compounds of broken green tea and explore the effect of isolated scenting on metabolic profile and taste quality of broken green tea in this research. A total of 236 nonvolatile compounds were identified and 13 compounds were believed to be the key characteristic taste compounds of scented broken green tea. Meanwhile, the optimal isolated scenting time of broken green tea was determined to be 10h based on the sensory evaluation and PLS results. The contents and types of flavonoids, organic acids and catechins lead to the difference of taste quality at different scenting times. Overall, these findings provided a theoretical basis for scenting to improve the taste of broken green tea, and provide a new idea for improving the taste of broken green tea.
关键词：
Black tea;Hypoglycemic activity;Interaction mechanism;Theaflavins;α-amylase
摘要：
Hyperglycemia can cause early damage to human bady and develop into diabates that will severely threaten human healthy. The effectively clinical treatment of hyperglycemiais is by inhibiting the activity of alpha-amylase. Black tea has been reported to show inhibitory effect on alpha-amylase and can be used for hyperglycemia treatment. However, the mechanism underlying is unclear. In this study, in vivo experiment showed that black tea theaflavins extract (BTE) effectively alleviated hyperglycemia. In vitro experiment showed that the effects may be caused by the interation between theaflavins and alpha-amylase. While TF1 and TF3 were mixed type inhibitors of alpha-amylase, TF2A and TF2B were competitive inhibitors of alpha-amylase. Molecular docking analysis showed that theaflavins monomers interacted with the hydrophobic region of alpha-amylase. Further study verified that monomer-alpha-amylase complex was spontaneously formed depending on hydrophobic interactions. Taken together, theaflavins showed potential anti-hyperglycemia effect via inhibiting alpha-amylase activity. Our results suggested that theaflavins might be utilized as a new type of alpha-amylase inhibitor to prevent and cure hyperglycemia.
摘要：
Yellow tea is a lightly fermented tea with unique sensory qualities and health benefits. However, chemical composition and sensory quality of yellow tea products have rarely been studied. 12 representative yellow teas, which were basically covered the main products of yellow tea, were chosen in this study. Combined analysis of non-targeted/targeted metabolomics and electronic sensor technologies (E-eye, E-nose, E-tongue) revealed the chemical and sensor variation. The results showed that yellow big tea differed greatly from yellow bud teas and yellow little teas, but yellow bud teas could not be effectively distinguished from yellow little teas based on chemical constituents and electronic sensory characteristics. Sensor variation of yellow teas might be attributed to some compounds related to bitterness and aftertaste-bitterness (4'-dehydroxylated gallocatechin-3-O-gallate, dehydrotheasinensin C, myricitin 3-O-galactoside, phloroglucinol), aftertaste-astringency (methyl gallate, 1,5-digalloylglucose, 2,6-digalloylglucose), and sweetness (maltotriose). This study provided a comprehensive understanding of yellow tea on chemical composition and sensory quality.
摘要：
Obesity is associated with gut dysbiosis and metabolic endotoxin. Junshanyinzhen tea extract ( JSTE) reduced fat accumulation and body weight in obese mice. However, the effects and mechanism of JSTE in preventing obesity were unclear. Therefore, we used different doses of JSTE (75, 150 and 300 mg/(kg<middle dot>day)) to evaluate the effect on high-fat diet (HFD)-induced rats under 8 weeks of intervention. Here, our results showed that JSTE could significantly reduce body weight gain, blood lipid levels and fat accumulation, improve fatty damage in liver tissue (P < 0.05). In addition, JSTE increased the expression of intestinal tight junction proteins (P < 0.05), relieved metabolic endotoxemia (P < 0.05) and chronic low-grade inflammation in HFD rats. Sequencing of fecal samples showed that JSTE could effectively reverse the microbial diversity and the ratio of Firmicutes to Bacteroidetes to normal levels in HFD-fed rats. Desulfovibrioceae and Erysipelotrichaceae, which are positively related to obesity, were decreased by JSTE intervention (P < 0.05). while Bifidobacteriaceae, Bacteroidaceae, Akkermansia, and Clostridium, which are negatively related to obesity, were increased. Together, these results suggested that JSTE might effectively prevent obesity by modulating gut microbiota dysbiosis, intestinal barrier dysfunction, metabolic endotoxemia and chronic lowgrade inflammation in HFD-induced rats. (c) 2024 Beijing Academy of Food Sciences. Publishing services by Tsinghua University Press. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
关键词：
Fu Brick Tea;Sensomics analysis;Aroma recombination and omission;Key odor-active compounds;Bacterial community
摘要：
Fu Brick Tea (FBT) is a unique fermented tea produced in multiple regions of China, whose aroma qualities, key odor-active compounds and bacterial communities are not well characterized. By optimizing HS-SPME methods, utilizing GC-MS, GC-O, sensory analysis, aroma recombination and omission experiments, and bacterial sequencing, we revealed the primary volatiles and bacterial communities in 41 samples from 7 major producing regions. A total of 63 volatiles and 32 odor-active compounds were quantitatively analyzed using GC-MS and GC-O, respectively. Sensory analyses discriminated the quality of the samples. Differential analysis indicated that poor aroma FBTs had either low volatile content or excessive "green" notes. Key odor-active compounds in highquality aroma FBTs include 1-octen-3-ol, phenylethylalcohol, beta-ionone, dihydroactindiolide, and 1,2,3-trimethoxybenzene. Sequencing results identified Bacillus, Pseudomonas, and Streptococcus as dominant genera. Functional prediction analyses suggest that bacteria contribute to the formation of FBT aroma. This study offers new insights into the quality characteristics of FBT.
通讯机构：
[Yin, X ; Liu, ZH ] H;Hunan Agr Univ, Key Lab Tea Sci, Minist Educ, Changsha 410128, Peoples R China.;Natl Res Ctr Engn & Technol Utilizat Bot Funct Ing, Changsha 410128, Peoples R China.;Hunan Acad Agr Sci, Tea Res Inst, Dept Tea Qual Chem & Nutr Hlth, Hunan Tea Plant & Tea Proc Observat Stn,Minist Agr, Changsha 410125, Peoples R China.;Minist Utilizat Bot Funct Ingredients, Coinnovat Ctr Educ, Changsha 410128, Peoples R China.
关键词：
Shaken Hunan black tea;leaves grade;taste;aroma;HS-SPME/GC-MS
摘要：
<jats:p>Shaken Hunan black tea is an innovative Hunan black tea processed by adding shaking to the traditional Hunan black tea. The quality of shaken black tea is influenced by leaf grades of different maturity. In this study, the taste and aroma quality of shaken Hunan black tea processed with different grades were analyzed by sensory evaluation (SP, HPLC, and HS-SPME/GC-MS). The results showed that shaken Hunan black tea processed with one bud and two leaves has the best quality, which has a sweet, mellow, and slightly floral taste, as well as a floral, honey, and sweet aroma. Moreover, caffeine and EGCG were identified as the most important bitter and astringent substances in shaken Hunan black. Combined with the analysis of GC-MS and OAV analysis, geraniol, jasmone, β-myrcene, citral, and trans-β-ocimene might be the most important components that affect the sweet aroma, while methyl jasmonate, indole, and nerolidol were the key components that affect the floral aroma of shaken Hunan black tea. This study lays a foundation for this study of the taste and aroma characteristics of shaken Hunan black tea and guides enterprises to improve shaken black tea processing technology.</jats:p>
摘要：
Recently, research has confirmed that jasmine tea may help improve the depressive symptoms that are associated with psychiatric disorders. Our team previously found that jasmine tea improved the depressive-like behavior that is induced by chronic unpredictable mild stress (CUMS) in Sprague Dawley (SD) rats. We hypothesized that the metabolic disorder component of depression may be related to the gut microbiota, which may be reflected in the metabolome in plasma. The influence of jasmine tea on gut microbiota composition and the association with depressive-related indexes were explored. Furthermore, the metabolites in plasma that are related to the gut microbiota were identified. SD rats were treated with control or CUMS and administrated jasmine tea for 8 weeks. The 16S rRNA gene amplicon sequencing was used to analyze the gut microbiota in feces samples, and untargeted metabolomics was used to analyze the metabolites in plasma. The results found that jasmine tea significantly ameliorated the depressive behavior induced by CUMS, significantly improved the neurotransmitter concentration (BDNF and 5-HT), and decreased the pro-inflammation levels (TNF-α and NF-κB). The intervention of jasmine tea also alleviated the dysbiosis caused by CUMS; increased the relative abundance of Bacteroides, Blautia, Clostridium, and Lactobacillus; and decreased Ruminococcus and Butyrivibrio in the CUMS-treated rats. Furthermore, the serum metabolites of the CUMS-treated rats were reversed after the jasmine tea intervention, i.e., 22 were up-regulated and 18 were down-regulated, which may have a close relationship with glycerophospholipid metabolism pathways, glycine serine and threonine metabolism pathways, and nicotinate and nicotinamide metabolism pathways. Finally, there were 30 genera of gut microbiota related to the depressive-related indexes, and 30 metabolites in the plasma had a strong predictive ability for depressive behavior. Potentially, our research implies that the intervention of jasmine tea can ameliorate the depression induced by CUMS via controlling the gut flora and the host's metabolism, which is an innovative approach for the prevention and management of depression.
摘要：
Phyllosphere microorganisms have recently attracted the attention of scientists studying plant microbiomes. The origin, diversity, functions, and interactions of phyllosphere microorganisms have been extensively explored. Many experiments have demonstrated seasonal cycles of phyllosphere microbes. However, a comprehensive comparison of these separate investigations to characterize seasonal trends in phyllosphere microbes of woody and herbaceous plants has not been conducted. In this review, we explored the dynamic changes of phyllosphere microorganisms in woody and non-woody plants with the passage of the season, sought to find the driving factors, summarized these texts, and thought about future research trends regarding the application of phyllosphere microorganisms in agricultural production. Seasonal trends in phyllosphere microorganisms of herbaceous and woody plants have similarities and differences, but extensive experimental validation is needed. Climate, insects, hosts, microbial interactions, and anthropogenic activities are the diverse factors that influence seasonal variation in phyllosphere microorganisms.
摘要：
In this study, non-covalent binding mechanism of lactoferrin (LaF)-theaflavin (TF) complex and its functional properties were investigated. Multi-spectroscopic analyses showed that the secondary structure of LaF was altered with increasing TF concentration. The non-covalent binding of TF to LaF resulted in a reduction in the content of the alpha-helix and beta-sheet, as well as a decrease in the fluorescence intensity of LaF. DSC result showed that non-covalent binding of TF improved thermal stability of LaF. Molecular dynamics simulations confirmed that the stable binding of LaF-TF was driven by hydrogen bonding and hydrophobic interactions. Additionally, non-covalent binding of TF increased the antioxidant capacity and emulsifying properties of LaF. Dynamic interfacial tension indicated that the strong interaction between LaF and TF reduced the interfacial tension, but improved the rheological properties of LaF. The functional characteristics of the non-covalent complex was effectively enhanced, paving the way for its potential use in the food industry.
摘要：
Background: Selenium is an essential trace element for human health and its deficiency leads to increased risk of many diseases worldwide. Tea (Camellia sinensis (L.) O. Kuntze) is a plant with selenium accumulation ability. Selenium-enriched tea combines the flavor and health benefits of tea with the additional wellness advantages of selenium, holding promising market potential. Scope and approach: This article reviews the latest research advances on selenium-enriched tea. The ability and mechanism of selenium accumulation in tea plants, as well as the existence forms of selenium in tea leaves, have been summarized. In addition, we examined the effects of selenium on tea physiological activities, including metabolic and quality regulation, and provided a summary of the associated health benefits. Key findings and conclusions: Tea plants possess a strong ability to accumulate selenium in selenium-rich area or under selenium fertilizer application. Over 80% of the selenium in selenium-enriched tea leaves exists in organic forms, including selenoamino acids, selenoproteins, selenium-polysaccharides, and selenium-polyphenols. Selenium can promote tea growth and optimize the proportion of quality compounds (e.g., polyphenols, amino acids, and alkaloids). The levels of stress-related antioxidant enzymes and phytohormones are increased to promote environmental stress resistance and selenium tolerance. Selenium-enriched tea demonstrates superior health benefits compared to regular tea due to the synergistic effects of tea active ingredients and selenium element. This review aims to inspire innovative ideas for the development of selenium-enriched tea with thriving growth conditions, high selenium bioaccessibility, delightful flavor, and broad applications in the food and health industries.
摘要：
Background: The worldwide prevalence of metabolic syndrome (MS) and obesity has led to the exploration of tea consumption as a potential strategy for managing these conditions. However, the clinical outcomes remain debated. We conducted a meta-analysis to evaluate the benefits of tea supplementation in MS and obesity entirely based on randomized controlled trials (RCTs). Methods: Databases of PubMed, Cochrane library, MEDLINE and Web of Science were searched through May 2023 to identify eligible RCTs evaluating the effects of tea supplementation related to MS and obesity. Results were summarized using standardized mean differences (SMDs) by suitable effect model. Results: A total of 24 RCTs were screened, including 1672 subjects from 8 countries. Tea supplementation reduced body weight (BW) (SMD:-0.14; 95%CI:-0.26,-0.03; P = 0.013), body mass index (BMI) (SMD:- 0.15; 95%CI:-0.26,-0.03; P = 0.016), triglycerides (TG) (SMD:-0.21; 95% CI:-0.41,-0.01; P = 0.044), total cholesterol (TC) (SMD:-0.23; 95% CI:-0.44,-0.02; P = 0.033), low-density lipoprotein cholesterol (LDLC) (SMD:-0.28; 95% CI:-0.5,-0.05; P = 0.016) and hemoglobin A1c (HbA1c) (SMD:-0.35; 95% CI:-0.60,- 0.1; P = 0.007) levels, increased high-density lipoprotein (HDL) (SMD: 0.13; 95% CI: 0.01, 0.25; P = 0.04) levels versus Placebo. Conclusion: This meta-analysis presents convincing evidence of the potential advantages of tea consumption for individuals with MS and obesity. Compared with control group, tea consumption can significantly reduce BW, BMI, and lipid profiles (HDL-C, LDL-C, TG, TC) levels of obesity and MS patients. This beneficial effect highlights the prospect of tea as a beneficial dietary strategy in addressing these medical conditions.
摘要：
Theaflavins, a major kind of component in black tea, have been reported to show a variety of biological activities and health effects. However, the unstable chemical properties, low bioavailability and unclear metabolism pathways of theaflavins have left much to be desired in terms of its specific efficacy and applications. This paper provides a comprehensive knowledge on the digestion, absorption, metabolism, distribution and excretion of theaflavins. We find that pH-dependent stability, efflux transport proteins are closely related to the low absorption rate and low bioavailability of theaflavins. When pass through the gastrointestinal tract, TFDG, TF2A and TF2B are gradually degraded to TF1, and release gallic acid. Then, the theaflavins skeleton are degraded into small molecular phenolic substances under the action of enzymes and microorganisms. In addition, theaflavins are widely distributed in the human body including brain, lung, heart, kidney, liver, blood tissue in a low content and can be excreted through feces. However, the influence of digestive enzymes barrier and gut microbial barrier on theaflavins are still unclear. Importantly, most findings are reported by in vitro methods and animal experiments, the metabolites and metabolic pathways of theaflavins in human body are not fully understood and need to be further investigated. We hope to lay a theoretical basis for exploring methods to improve the bioavailability of theaflavins and expanding the application of theaflavins in health foods as well as pharmaceuticals.
摘要：
Dark tea (DT) holds a rich cultural history in China and has gained sizeable consumers due to its unique flavor and potential health benefits. In this study, headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS), relative odor activity value (ROAV), and chemometrics approaches were used to detect and analyze aroma compounds differences among five dark teas from different geographical regions. The results revealed that the five DTs from different geographical regions differed in types, quantities, and relative concentrations of volatile compounds. A total of 1372 volatile compounds of were identified in the 56 DT samples by HS-SPME-GC-MS. Using ROAV and chemometrics approaches, based on ROAV>1 and VIP>1. Eighteen key aroma compounds can be used as potential indicators for DT classification, including dihydroactinidiolide, linalool, 1,2,3-trimethoxybenzene, geranyl acetone, 1,2,4-trimethoxybenzene, cedrol, 3,7-dimethyl-1,5,7-octatrien-3-ol, β-ionone, 4-ethyl-1,2-dimethoxybenzene, methyl salicylate, α-ionone, geraniol, linalool oxide I, linalool oxide II, 6-methyl-5-hepten-2-one, α-terpineol, 1,2,3-trimethoxy-5-methylbenzene, and 1,2-dimethoxybenzene. These compounds provide a certain theoretical basis for distinguishing the differences in five DTs from different geographical regions. This study provides a potential method for identifying the volatile substances in DTs and elucidating the differences in key aroma compounds. Abbreviations: DT, dark tea; FZT, Fuzhuan tea; LPT, Guangxi Liupao tea; QZT, Hubei Qingzhuan tea; TBT, Sichuan Tibetan tea; PET, Yunnan Pu-erh tea; ROAV, Relative odor activity value; OT, Odor threshold; HS-SPME, Headspace solid-phase microextraction; GC-MS, Gas chromatography-mass spectrometry; PCA, Principal components analysis; PLS-DA, Partial least squares-discriminant analysis; HCA, Hierarchical clustering analysis.
关键词：
Camellia sinensis;Electronic eye;Electronic nose;Nontargeted analysis;Polyphenols;Six types of tea;Targeted analysis
摘要：
Tea polyphenols transform under processing methods, but a systematic study on their changes in the same large-leaf tea cultivar is lacking. Here, Camellia sinensis var. assamica cv. Yunkang-10 leaves underwent six processing methods and were assessed using optimized nontargeted (UHPLC-Q-Exactive Orbitrap-MS) and targeted (UHPLC-QqQ-MS) polyphenomics, along with molecular networking analysis. 903 and 52 polyphenolic compounds (catechins, flavones and flavonols, and phenolic acids) were respectively relatively and absolutely quantified for the first time. Dark and black teas, with the lowest polyphenol content, differed from the other four tea types, although variations existed among these four teas. However, some flavonol and flavone aglycones (e.g. kaempferol, apigenin), as well as some phenolic acids (e.g. ellagic acid, gallic acid), exhibited higher levels in dark and black teas. Correlations between polyphenolic composition and electronic sensory characteristics were observed using E-tongue and E-eye. This study enriches understanding of polyphenol profiles in Chinese teas post diverse processing.
摘要：
Dietary management and interventions are crucial in the clinical management of diabetes. Numerous active dietary components in black tea have demonstrated positive effects on blood glucose levels and metabolic functions. However, limited research has explored the potential of theaflavins (TF), polyphenols in black tea, for diabetes management. In this study, high-purity TF was administered to Goto-Kakizaki (GK) diabetic model rats for four weeks to investigate its impact on diabetic pathology and analyze the underlying mechanisms through liver transcriptomics, hepatocyte metabolomics, and gut microbiome analysis. The findings indicated that continuous administration of TF (100mg/kg) significantly suppressed blood glucose levels, reduced insulin resistance, and decreased the expression of oxidative stress indicators and inflammatory factors in GK rats. Further analysis revealed that TF might alleviate insulin resistance by improving hepatic glycogen conversion and reducing hepatic lipid deposition through modulation of key pathways, such as peroxisome proliferator-activated receptors and PI3K/AKT/GSK-3 pathways within the liver, thereby ameliorating diabetic symptoms. Additionally, TF intake facilitated the restoration of the intestinal microbial community structure by reducing the abundance of harmful bacteria and increasing the abundance of beneficial bacteria. It also reduced endotoxin lipopolysaccharide production, thereby lowering the chances of insulin resistance development and enhancing its efficacy in regulating blood glucose levels. These findings offer a novel perspective on the potential of black tea and its active constituents to prevent and treat diabetes and other metabolic disorders, providing valuable references for identifying and applying active dietary components from tea.
摘要：
Epigallocatechin-3-gallate (EGCG) is a main bioactive constituent in green tea. Being a redox-active polyphenol, high-dose EGCG exhibits pro-oxidative activity and could cause liver injury. L-theanine is a unique non-protein amino acid in green tea and could provide liver-protective effects. The purpose of this study was to investigate the hepatoprotective effects of L-theanine on EGCG-induced liver injury and the underlying mechanisms. A total of 300 mg/kg L-theanine was administrated to ICR mice for 7 days. Then, the acute liver injury model was established through intragastric administration of 1000 mg/kg EGCG. Pretreatment with L-theanine significantly alleviated the oxidative stress and inflammatory response caused by high-dose EGCG through modulation of Nrf2 signaling and glutathione homeostasis. Furthermore, metabolomic results revealed that L-theanine protects mice from EGCG-induced liver injury mainly through the regulation of amino acid metabolism, especially tryptophan metabolism. These findings could provide valuable insights into the potential therapeutic applications of L-theanine and highlight the importance of the interactions between dietary components.
作者机构：
[Wang, Kunbo; Shang, Bohao; Zhu, Mingzhi; Liu, Zhonghua; Zhou, Fang; Huang, Jianan] Hunan Agr Univ, Coll Hort, Changsha 410128, Peoples R China.;[Zhu, Mingzhi; Zeng, Xin] Huaibei Normal Univ, Coll Life Sci, Huaibei 235000, Peoples R China.;[Yin, Feiyan; Cao, Jin; Yuan, Yong] Hunan Tea Grp Co Ltd, Changsha 410128, Peoples R China.;[Li, Maiquan] Hunan Agr Univ, Sch Food Sci & Technol, Changsha 410128, Peoples R China.
通讯机构：
[Zeng, X ; Li, MQ ; Liu, ZH ] H;Hunan Agr Univ, Coll Hort, Changsha 410128, Peoples R China.;Huaibei Normal Univ, Coll Life Sci, Huaibei 235000, Peoples R China.;Hunan Agr Univ, Sch Food Sci & Technol, Changsha 410128, Peoples R China.
关键词：
Golden -flower fungus;Aspergillus cristatus;Polysaccharides;Obesity;Gut microbiota
摘要：
Golden -flower fungus, the only dominant microorganism determining the Fu -brick tea quality through fermentation and the important microbe in Liupao tea, is considered a potential probiotic fungus based on its anti -obesity effect. However, the classification of golden -flower fungi is still controversial; the anti -obesity effect of golden -flower fungus polysaccharides remains unknown. In this study, we identify a golden -flower strain as Aspergillus cristatus based on morphological characteristics and multigene phylogeny analysis, which resolves the controversy of classification. Moreover, we find A. cristatus polysaccharides (ACPS) attenuate obesity in rats. ACPS modulate gut bacterial composition, in which Akkermansia, Akkermansia muciniphila, Bacteroides, Romboutsia, Blautia, and Desulfovibrio are considered the core microbes regulated by ACPS. ACPS increase fecal total short -chain fatty acid content and serum, hepatic, and fecal total bile acid content. Furthermore, ACPS-induced gut microbiota alteration plays a causal role in the protection from obesity, according to a fecal transplantation experiment. Thus, ACPS ameliorate obesity by regulating gut microbiota and gut microbiota-related metabolites. (c) 2024 Beijing Academy of Food Sciences. Publishing services by Tsinghua University Press. This is an open access article under the CC BY -NC -ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
